title: Anomalous fast dynamics of adsorbate overlayers near an incommensurate structural transition.
abstract: We investigate the dynamics of a compressively strained adsorbed layer on a periodic substrate via a simple two-dimensional model that admits striped and hexagonal incommensurate phases. We show that the mass transport is superfast near the striped-hexagonal phase boundary and in the hexagonal phase. For an initial step profile separating a bare substrate region (or "hole") from the rest of a striped incommensurate phase, the superfast domain wall dynamics leads to a bifurcation of the initial step profile into two interfaces or profiles propagating in opposite directions with a hexagonal phase in between. This yields a theoretical understanding of the recent experiments for the Pb/Si(111) system.
authors.affiliation: Laboratório Associado de Sensores e Materiais, Instituto Nacional de Pesquisas Espaciais, 12245-970 São José dos Campos, São Paulo, Brazil and Department of Physics, Post Office Box 1843, Brown University, Providence, Rhode Island 02912-1843, USA.
authors.forename: Enzo
authors.initials: E
authors.lastname: Granato
authors.forename: S C
authors.initials: SC
authors.lastname: Ying
authors.forename: K R
authors.initials: KR
authors.lastname: Elder
authors.forename: T
authors.initials: T
authors.lastname: Ala-Nissila